High step-up ratio multiplication of voltage structure passive and nondestructive clamping converter
Technical field
The present invention relates to a kind of DC-to-DC converter and application, is high step-up ratio multiplication of voltage structure passive and nondestructive clamping converter specifically.
Background technology
In solar power system, because the output voltage of monolithic solar cell is lower, and the required voltage of inversion grid connection generating is higher, therefore needs the one-level DC-to-DC converter low voltage and direct current to be converted to the high-voltage direct-current electricity that is fit to be incorporated into the power networks.In the distributed solar energy electricity generating plan, the power capacity of monolithic solar cell is less, but having relatively high expectations to efficient.Therefore how to realize high-gain, high efficiency and single-phase single-grade converter simple in structure, significant for the development that promotes photovoltaic industry.
The voltage gain of conventional single-phase single-tube booster type (Boost) DC-DC converter only has duty ratio to determine that voltage gain is limited, is difficult to satisfy the conversion requirement of high-gain.The voltage stress of power switch pipe is larger, is difficult to adopt the high performance switching tube of low pressure to reduce conduction loss.And converter is operated in the hard switching state, and switching loss is larger.In order to realize the soft switch motion of Boost converter, in recent years, some have in succession been studied by being attached with the soft switch solution of source power switch or passive device, although these circuit have been realized soft switch motion, but can not reduce the voltage stress of switching tube, can not realize the high-gain conversion of system.For the voltage gain of Lifting Transform device, a kind of scheme is to adopt the scheme of switching capacity, but the required switching tube quantity of this scheme is more, has increased system cost; Other scheme is to adopt three complicated winding coupled inductance schemes, and the shortcoming of this scheme is the coupling inductance complex structure, is unfavorable for industrial processes, is difficult to guarantee the consistency of circuit.
Summary of the invention
It is little that the present invention overcomes conventional single-phase single-tube booster type DC-DC converter voltage gain, conducting power consumption and switch power consumption large shortcoming, provide a kind of simple in structure, control the high step-up ratio multiplication of voltage structure passive and nondestructive clamping converter of convenient and noenergy loss.
High step-up ratio multiplication of voltage structure passive and nondestructive clamping converter of the present invention, the first end of coupling inductance the first winding links to each other with the positive pole of power supply, the second end of the first winding links to each other with the drain electrode of power switch pipe and the anode of clamping diode, the negative electrode of clamping diode links to each other with the anode of the first end of clamping capacitance and fly-wheel diode, and the second end of the source electrode of power switch pipe and the negative pole of power supply and clamping capacitance links to each other;
One end of coupling inductance the second winding links to each other with the negative pole of power supply, coupling inductance the second winding the second end links to each other with the first end of multiplication of voltage electric capacity, the second end of multiplication of voltage electric capacity links to each other with the negative electrode of fly-wheel diode, coupling inductance the second winding and coupling inductance the first winding are all two windings in the coupling inductance, the Same Name of Ends take the first end of the first end of the first winding and the second winding as coupling inductance;
The anode of output diode links to each other with the negative electrode of fly-wheel diode, and the negative electrode of output diode links to each other with the first end of output capacitance, and the second end of output capacitance links to each other with the first end of clamping capacitance.
Described converter, the one or more synchronous rectifiers that make in its clamping diode, fly-wheel diode and the output diode all can work.
During converter work of the present invention, utilize the transformer action of coupling inductance to expand the converter voltage gain, reduced the voltage stress of power switch pipe and clamping diode, reduced the conduction loss of power device.The introducing of voltage-multiplying circuit unit has further improved the voltage gain of circuit and has reduced the voltage stress of device; Utilize the leakage inductance of coupling inductance to realize the zero current turning-on of power switch pipe; Utilize simultaneously the leakage inductance of coupling inductance also to realize the soft shutoff of fly-wheel diode and output diode; Utilize the energy of clamping diode and clamping capacitance absorption leakage inductance, no-voltage spike when power switch pipe is turn-offed, and the leakage inductance energy that absorbs finally is delivered to load, the realization Lossless Snubber; Its circuit structure is simple, and control is convenient, is applicable to small-power, high-gain and the high efficiency distributed photovoltaic occasion of generating electricity by way of merging two or more grid systems.
Advantage of the present invention is: need not extra power switch and inductance element, attachment element is few, simple in structure, control is convenient, noenergy losser in the circuit can improve the efficient of circuit, and in the commutation course, no-voltage overshoot when power switch pipe turn-offs, no current overshoot when fly-wheel diode is opened; Coupling inductance transferring energy all when the switching tube of correspondence turns on and off has improved the utilance of coupling inductance, has reduced the volume of coupling inductance.
Description of drawings
Fig. 1 is circuit diagram of the present invention;
Embodiment
Referring to Fig. 1, high step-up ratio multiplication of voltage structure passive and nondestructive clamping converter of the present invention, wherein:
Coupling inductance the first winding L
1First end link to each other the first winding L with the positive pole of power supply Vin
1The second end link to each other with the drain electrode of power switch tube S and the anode of clamping diode Dc, the negative electrode of clamping diode Dc links to each other with the first end of clamping capacitance Cc and the anode of sustained diode r, and the negative pole of the source electrode of power switch tube S and power supply Vin and the second end of clamping capacitance Cc link to each other;
Coupling inductance the second winding L
2An end link to each other coupling inductance the second winding L with the negative pole of power supply Vin
2The second end links to each other with the first end of multiplication of voltage capacitor C m, and the second end of multiplication of voltage capacitor C m links to each other with the negative electrode of sustained diode r, coupling inductance the second winding L
2With coupling inductance the first winding L
1Be all two windings in the coupling inductance, among the figure by " * " mark the first winding L
1With the second winding L
2Same Name of Ends;
The anode of output diode Do links to each other with the negative electrode of sustained diode r, and the negative electrode of output diode Do links to each other with the first end of output capacitance Co, and the second end of output capacitance Co links to each other with the first end of clamping capacitance Cc.
The voltage of output capacitance Co is Vout, and energy finally passes to load Ro.
High step-up ratio multiplication of voltage structure passive and nondestructive clamping converter has five kinds of courses of work in a switch periods, i.e. the change of current between power switch tube S shutoff and clamping diode Dc open; The change of current between sustained diode r shutoff and the output diode Do conducting; Clamping diode Dc turn off process; Commutation course between output diode Do shutoff and power switch tube S are opened, sustained diode r turn on process.
The change of current between power switch tube S shutoff and clamping diode Dc open:
Before the change of current, circuit is in power switch tube S and sustained diode r conducting, the steady-working state that clamping diode Dc and output diode Do turn-off.When power switch tube S is turn-offed, voltage rises rapidly on the power switch tube S, the voltage at clamping diode Dc two ends is dropped rapidly to zero, clamping diode Dc is open-minded, because the effect of clamping capacitance Cc, the voltage at power switch tube S two ends is certain voltage value by clamp, has realized that the soft clamping of power switch tube S turn-offs.
The change of current between sustained diode r shutoff and the output diode Do conducting:
After clamping diode Dc opens, voltage on the clamping capacitance Cc rises so that certain slope is linear from certain value, the leakage inductance energy of coupling inductance is transferred on the clamping capacitance Cc, and the electric current of sustained diode r drops to zero with certain slope linearity, and sustained diode r turn-offs.And the voltage linear at output diode Do two ends drops to zero, and output diode Do is open-minded, and energy begins to transfer to output.Circuit enters into power switch tube S and sustained diode r turn-offs, the steady-working state of clamping diode Dc and output diode Do conducting.
Clamping diode Dc turn off process:
After the output diode Do conducting, electric current on the clamping diode Dc descends so that certain slope is linear, when the electric current on the clamping diode Dc dropped to zero, clamping diode Dc turn-offed naturally, and energy is transferred to load Ro by coupling inductance the second winding from multiplication of voltage capacitor C m.Circuit enters the first switching tube S, and clamping diode Dc and sustained diode r turn-off, the steady-working state of output diode Do conducting.
Commutation course between output diode Do shutoff and power switch tube S are opened:
The gate signal of power switch tube S provides, the electric current of power switch tube S rises from zero so that certain slope is linear, realized the zero current turning-on of power switch tube S, the electric current of output diode Do descends so that certain slope is linear, when the electric current of output diode Do drops to zero, output diode Do turn-offs, and has realized that output diode Do turn-offs and the change of current of power switch tube S between opening, and has reduced the reverse recovery loss of output diode Do.
Sustained diode r turn on process:
Power switch tube S is opened with output diode Do pass and is had no progeny, and coupling inductance is operated in the normal shock transformer state, and the voltage linear at sustained diode r two ends drops to zero, and sustained diode r is open-minded, and energy begins to transfer to multiplication of voltage capacitor C m.Circuit ingoing power switching tube S and sustained diode r conducting, the steady-working state that clamping diode Dc and output diode Do turn-off.